The present invention relates generally to current collecting apparatus for railway vehicles and more particularly to a current collecting apparatus fit for use in a vehicle on a high-speed railway.
Railway vehicles using electric power as a power source are generally equipped with current collecting apparatus on their roofs for collecting electric power by contact with overhead power lines. Japanese Patent Laid-Open No. 304101/1992 discloses a noise reducing arrangement attainable by installing sound arresters (covers) in front and behind a current collecting apparatus as means for suppressing noise. This noise reducing arrangement is such that sound arresters are respectively installed in front and behind a current collecting apparatus to place the current collecting apparatus in the airflow decelerated thereby so as to prevent not only aerodynamic noise from being produced from the current collecting apparatus but also the aerodynamic noise from radiating therefrom.
The prior art current collecting apparatus disclosed in the aforementioned patent publication is obviously intended to reduce the noise generated from the current collecting apparatus during relatively high-speed traveling. However, in the case of a high-speed railway in the next generation on which the operation is aimed at a speed of as high as 350 km/hr, there still arises a problem of aerodynamic noise originating from such noise arresters themselves and the measure taken to reduce noise by means of the current collecting apparatus can hardly be effective in high-velocity zones. Since the air resistance generated while vehicles are traveling increases in proportion to the square of the velocity, moreover, an increase in operating cost due to travel resistance originating from the sound arresters would pose a serious problem in the case of the Shinkansen in the next generation in which the commercial operation is aimed at a speed well over the present one, for example, as high as 350 km/hr.
In view of the foregoing problems, an object of the present invention is to provide a current collecting apparatus so designed as to reduce not only noise but also air resistance springing therefrom on any high-speed railway in the next generation.